#include "llvm/Support/raw_ostream.h"
#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/ADT/Statistic.h"
-#include <set>
using namespace llvm;
STATISTIC(NumInlined, "Number of functions inlined");
// Threshold to use when optsize is specified (and there is no -inline-limit).
const int OptSizeThreshold = 75;
-Inliner::Inliner(void *ID)
+Inliner::Inliner(char &ID)
: CallGraphSCCPass(ID), InlineThreshold(InlineLimit) {}
-Inliner::Inliner(void *ID, int Threshold)
- : CallGraphSCCPass(ID), InlineThreshold(Threshold) {}
+Inliner::Inliner(char &ID, int Threshold)
+ : CallGraphSCCPass(ID), InlineThreshold(InlineLimit.getNumOccurrences() > 0 ?
+ InlineLimit : Threshold) {}
/// getAnalysisUsage - For this class, we declare that we require and preserve
/// the call graph. If the derived class implements this method, it should
/// available from other functions inlined into the caller. If we are able to
/// inline this call site we attempt to reuse already available allocas or add
/// any new allocas to the set if not possible.
-static bool InlineCallIfPossible(CallSite CS, CallGraph &CG,
- const TargetData *TD,
- InlinedArrayAllocasTy &InlinedArrayAllocas) {
+static bool InlineCallIfPossible(CallSite CS, InlineFunctionInfo &IFI,
+ InlinedArrayAllocasTy &InlinedArrayAllocas,
+ int InlineHistory) {
Function *Callee = CS.getCalledFunction();
Function *Caller = CS.getCaller();
// Try to inline the function. Get the list of static allocas that were
// inlined.
- SmallVector<AllocaInst*, 16> StaticAllocas;
- if (!InlineFunction(CS, &CG, TD, &StaticAllocas))
+ if (!InlineFunction(CS, IFI))
return false;
// If the inlined function had a higher stack protection level than the
!Caller->hasFnAttr(Attribute::StackProtectReq))
Caller->addFnAttr(Attribute::StackProtect);
-
// Look at all of the allocas that we inlined through this call site. If we
// have already inlined other allocas through other calls into this function,
// then we know that they have disjoint lifetimes and that we can merge them.
//
SmallPtrSet<AllocaInst*, 16> UsedAllocas;
+ // When processing our SCC, check to see if CS was inlined from some other
+ // call site. For example, if we're processing "A" in this code:
+ // A() { B() }
+ // B() { x = alloca ... C() }
+ // C() { y = alloca ... }
+ // Assume that C was not inlined into B initially, and so we're processing A
+ // and decide to inline B into A. Doing this makes an alloca available for
+ // reuse and makes a callsite (C) available for inlining. When we process
+ // the C call site we don't want to do any alloca merging between X and Y
+ // because their scopes are not disjoint. We could make this smarter by
+ // keeping track of the inline history for each alloca in the
+ // InlinedArrayAllocas but this isn't likely to be a significant win.
+ if (InlineHistory != -1) // Only do merging for top-level call sites in SCC.
+ return true;
+
// Loop over all the allocas we have so far and see if they can be merged with
// a previously inlined alloca. If not, remember that we had it.
- for (unsigned AllocaNo = 0, e = StaticAllocas.size();
+ for (unsigned AllocaNo = 0, e = IFI.StaticAllocas.size();
AllocaNo != e; ++AllocaNo) {
- AllocaInst *AI = StaticAllocas[AllocaNo];
+ AllocaInst *AI = IFI.StaticAllocas[AllocaNo];
// Don't bother trying to merge array allocations (they will usually be
// canonicalized to be an allocation *of* an array), or allocations whose
// Otherwise, we *can* reuse it, RAUW AI into AvailableAlloca and declare
// success!
- DEBUG(dbgs() << " ***MERGED ALLOCA: " << *AI);
+ DEBUG(dbgs() << " ***MERGED ALLOCA: " << *AI << "\n\t\tINTO: "
+ << *AvailableAlloca << '\n');
AI->replaceAllUsesWith(AvailableAlloca);
AI->eraseFromParent();
MergedAwayAlloca = true;
++NumMergedAllocas;
+ IFI.StaticAllocas[AllocaNo] = 0;
break;
}
// If we already nuked the alloca, we're done with it.
if (MergedAwayAlloca)
continue;
-
+
// If we were unable to merge away the alloca either because there are no
// allocas of the right type available or because we reused them all
// already, remember that this alloca came from an inlined function and mark
if (Caller->hasLocalLinkage()) {
int TotalSecondaryCost = 0;
bool outerCallsFound = false;
- bool allOuterCallsWillBeInlined = true;
- bool someOuterCallWouldNotBeInlined = false;
+ // This bool tracks what happens if we do NOT inline C into B.
+ bool callerWillBeRemoved = true;
+ // This bool tracks what happens if we DO inline C into B.
+ bool inliningPreventsSomeOuterInline = false;
for (Value::use_iterator I = Caller->use_begin(), E =Caller->use_end();
I != E; ++I) {
- CallSite CS2 = CallSite::get(*I);
+ CallSite CS2(*I);
// If this isn't a call to Caller (it could be some other sort
- // of reference) skip it.
- if (CS2.getInstruction() == 0 || CS2.getCalledFunction() != Caller)
+ // of reference) skip it. Such references will prevent the caller
+ // from being removed.
+ if (!CS2 || CS2.getCalledFunction() != Caller) {
+ callerWillBeRemoved = false;
continue;
+ }
InlineCost IC2 = getInlineCost(CS2);
if (IC2.isNever())
- allOuterCallsWillBeInlined = false;
+ callerWillBeRemoved = false;
if (IC2.isAlways() || IC2.isNever())
continue;
float FudgeFactor2 = getInlineFudgeFactor(CS2);
if (Cost2 >= (int)(CurrentThreshold2 * FudgeFactor2))
- allOuterCallsWillBeInlined = false;
+ callerWillBeRemoved = false;
// See if we have this case. We subtract off the penalty
// for the call instruction, which we would be deleting.
if (Cost2 < (int)(CurrentThreshold2 * FudgeFactor2) &&
Cost2 + Cost - (InlineConstants::CallPenalty + 1) >=
(int)(CurrentThreshold2 * FudgeFactor2)) {
- someOuterCallWouldNotBeInlined = true;
+ inliningPreventsSomeOuterInline = true;
TotalSecondaryCost += Cost2;
}
}
// one is set very low by getInlineCost, in anticipation that Caller will
// be removed entirely. We did not account for this above unless there
// is only one caller of Caller.
- if (allOuterCallsWillBeInlined && Caller->use_begin() != Caller->use_end())
+ if (callerWillBeRemoved && Caller->use_begin() != Caller->use_end())
TotalSecondaryCost += InlineConstants::LastCallToStaticBonus;
- if (outerCallsFound && someOuterCallWouldNotBeInlined &&
+ if (outerCallsFound && inliningPreventsSomeOuterInline &&
TotalSecondaryCost < Cost) {
DEBUG(dbgs() << " NOT Inlining: " << *CS.getInstruction() <<
" Cost = " << Cost <<
return true;
}
-bool Inliner::runOnSCC(std::vector<CallGraphNode*> &SCC) {
+/// InlineHistoryIncludes - Return true if the specified inline history ID
+/// indicates an inline history that includes the specified function.
+static bool InlineHistoryIncludes(Function *F, int InlineHistoryID,
+ const SmallVectorImpl<std::pair<Function*, int> > &InlineHistory) {
+ while (InlineHistoryID != -1) {
+ assert(unsigned(InlineHistoryID) < InlineHistory.size() &&
+ "Invalid inline history ID");
+ if (InlineHistory[InlineHistoryID].first == F)
+ return true;
+ InlineHistoryID = InlineHistory[InlineHistoryID].second;
+ }
+ return false;
+}
+
+
+bool Inliner::runOnSCC(CallGraphSCC &SCC) {
CallGraph &CG = getAnalysis<CallGraph>();
const TargetData *TD = getAnalysisIfAvailable<TargetData>();
SmallPtrSet<Function*, 8> SCCFunctions;
DEBUG(dbgs() << "Inliner visiting SCC:");
- for (unsigned i = 0, e = SCC.size(); i != e; ++i) {
- Function *F = SCC[i]->getFunction();
+ for (CallGraphSCC::iterator I = SCC.begin(), E = SCC.end(); I != E; ++I) {
+ Function *F = (*I)->getFunction();
if (F) SCCFunctions.insert(F);
DEBUG(dbgs() << " " << (F ? F->getName() : "INDIRECTNODE"));
}
// Scan through and identify all call sites ahead of time so that we only
// inline call sites in the original functions, not call sites that result
// from inlining other functions.
- SmallVector<CallSite, 16> CallSites;
-
- for (unsigned i = 0, e = SCC.size(); i != e; ++i) {
- Function *F = SCC[i]->getFunction();
+ SmallVector<std::pair<CallSite, int>, 16> CallSites;
+
+ // When inlining a callee produces new call sites, we want to keep track of
+ // the fact that they were inlined from the callee. This allows us to avoid
+ // infinite inlining in some obscure cases. To represent this, we use an
+ // index into the InlineHistory vector.
+ SmallVector<std::pair<Function*, int>, 8> InlineHistory;
+
+ for (CallGraphSCC::iterator I = SCC.begin(), E = SCC.end(); I != E; ++I) {
+ Function *F = (*I)->getFunction();
if (!F) continue;
for (Function::iterator BB = F->begin(), E = F->end(); BB != E; ++BB)
for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I) {
- CallSite CS = CallSite::get(I);
+ CallSite CS(cast<Value>(I));
// If this isn't a call, or it is a call to an intrinsic, it can
// never be inlined.
- if (CS.getInstruction() == 0 || isa<IntrinsicInst>(I))
+ if (!CS || isa<IntrinsicInst>(I))
continue;
// If this is a direct call to an external function, we can never inline
if (CS.getCalledFunction() && CS.getCalledFunction()->isDeclaration())
continue;
- CallSites.push_back(CS);
+ CallSites.push_back(std::make_pair(CS, -1));
}
}
DEBUG(dbgs() << ": " << CallSites.size() << " call sites.\n");
+ // If there are no calls in this function, exit early.
+ if (CallSites.empty())
+ return false;
+
// Now that we have all of the call sites, move the ones to functions in the
// current SCC to the end of the list.
unsigned FirstCallInSCC = CallSites.size();
for (unsigned i = 0; i < FirstCallInSCC; ++i)
- if (Function *F = CallSites[i].getCalledFunction())
+ if (Function *F = CallSites[i].first.getCalledFunction())
if (SCCFunctions.count(F))
std::swap(CallSites[i--], CallSites[--FirstCallInSCC]);
InlinedArrayAllocasTy InlinedArrayAllocas;
+ InlineFunctionInfo InlineInfo(&CG, TD);
// Now that we have all of the call sites, loop over them and inline them if
// it looks profitable to do so.
// Iterate over the outer loop because inlining functions can cause indirect
// calls to become direct calls.
for (unsigned CSi = 0; CSi != CallSites.size(); ++CSi) {
- CallSite CS = CallSites[CSi];
+ CallSite CS = CallSites[CSi].first;
Function *Caller = CS.getCaller();
Function *Callee = CS.getCalledFunction();
CG[Caller]->removeCallEdgeFor(CS);
CS.getInstruction()->eraseFromParent();
++NumCallsDeleted;
+ // Update the cached cost info with the missing call
+ growCachedCostInfo(Caller, NULL);
} else {
// We can only inline direct calls to non-declarations.
if (Callee == 0 || Callee->isDeclaration()) continue;
+ // If this call site was obtained by inlining another function, verify
+ // that the include path for the function did not include the callee
+ // itself. If so, we'd be recursively inlining the same function,
+ // which would provide the same callsites, which would cause us to
+ // infinitely inline.
+ int InlineHistoryID = CallSites[CSi].second;
+ if (InlineHistoryID != -1 &&
+ InlineHistoryIncludes(Callee, InlineHistoryID, InlineHistory))
+ continue;
+
+
// If the policy determines that we should inline this function,
// try to do so.
if (!shouldInline(CS))
continue;
- // Attempt to inline the function...
- if (!InlineCallIfPossible(CS, CG, TD, InlinedArrayAllocas))
+ // Attempt to inline the function.
+ if (!InlineCallIfPossible(CS, InlineInfo, InlinedArrayAllocas,
+ InlineHistoryID))
continue;
++NumInlined;
+
+ // If inlining this function gave us any new call sites, throw them
+ // onto our worklist to process. They are useful inline candidates.
+ if (!InlineInfo.InlinedCalls.empty()) {
+ // Create a new inline history entry for this, so that we remember
+ // that these new callsites came about due to inlining Callee.
+ int NewHistoryID = InlineHistory.size();
+ InlineHistory.push_back(std::make_pair(Callee, InlineHistoryID));
+
+ for (unsigned i = 0, e = InlineInfo.InlinedCalls.size();
+ i != e; ++i) {
+ Value *Ptr = InlineInfo.InlinedCalls[i];
+ CallSites.push_back(std::make_pair(CallSite(Ptr), NewHistoryID));
+ }
+ }
+
+ // Update the cached cost info with the inlined call.
+ growCachedCostInfo(Caller, Callee);
}
// If we inlined or deleted the last possible call site to the function,
delete CG.removeFunctionFromModule(CalleeNode);
++NumDeleted;
}
-
- // Remove any cached cost info for this caller, as inlining the
- // callee has increased the size of the caller (which may be the
- // same as the callee).
- resetCachedCostInfo(Caller);
// Remove this call site from the list. If possible, use
// swap/pop_back for efficiency, but do not use it if doing so would
// move a call site to a function in this SCC before the
// 'FirstCallInSCC' barrier.
- if (SCC.size() == 1) {
- std::swap(CallSites[CSi], CallSites.back());
+ if (SCC.isSingular()) {
+ CallSites[CSi] = CallSites.back();
CallSites.pop_back();
} else {
CallSites.erase(CallSites.begin()+CSi);
projects / oota-llvm.git / blobdiff